Corner sealed leakproof carton



June 18, 1963 H. N. HOVLAND CORNER SEALED LEAKPROOF CARTON 2Sheets-Sheet 1 Filed Dec. 30, 1958 June 18, 1963 H. N. HovLAND coRNERSEALED LEAKPRooE CARTON 2 sheets-sheet 2 Filed Dec. 1?0,` 1958 UnitedStates Patent O 3,094,265 'CORNER SEALED LEAKPROOF CARTON Howard N.Hovland, Appleton, Wis., assignor to American Can Company,` New York,N.Y., a corporation of New Jersey Filed Dec. 30, 1958, Ser. No. 783,9006 Claims. (Cl. 229-37) This 'invention relates to a leakproof carton.and its method `of formation, particularly -for the packaging ofpulverulent, liquid and the like material. Cartons of this leakproofnature, vcommonly amade of paperboard material, which may beilined,vooatedor otherwise treated, are in substantial use for the packaging ofsuch materials as soap powders, ice cream, milk and other granulated andliquid products. Thepresent invention provides an unusual and economicalconstruction, easily formed, set up, Iilled and sealed by automaticequipment presently available or convenient modifications of suchequipment.

Details of the `advantages `and specific objects of the invention willbe readily apparent from the following description in connection with`the appended drawings, in Which:

vFIGURE 1 4is a plan view of the carton blank forming 'a part of thisinvention,

FIGURE 2 is an enlarged partial view of the part of the blank indicated'at A'in FIGURE `1,

FIGURE 3 V-is `a cross-sectional view taken along the line 3 3 of FIGURE2,

FIGURE 4 is ja cross-sectional view, showing a modiedconstruction takenalongthe line 4-4 of FIGURE 2,

FIGURE '5 is a cross-sectional view taken along the line 5-5` of FIGURE2,

`FIGURE 6 is a partial perspective View of an ,end of the carton shellformed from the blank of FIGURE Vl,

`FIGURES 7, '8 and v9 are partial perspective views showing successivesteps in the closing of an end of the carton,

yFIGURE 10 -is a perspective view showing the cornpleted carton formedfrom the blank of FIGURE 1,

FIGURE 11 is a partial plan view of a modified form of the carton blank,and

FIGURE l2 is a partial perspective view of a step in the formation of acarton from the modified blank ofv f15, 16, 17, `18 and 26 are lhingedlyconnected to the respective top and bottom end edges of the walls andpanel along hinge score lines 20y to 2,4.

yPanels 27 and Y33 are hingedpto the respective lateral edges of aps 18along hinge lines 34 and 35 :and yare integrally and hingedly connectedrespectively to flaps 26 and I17 along diagonal fold lor hinge -lines215 and 32. Sealing flaps 19 Vare hingedly .connected .to the remote endedges ofaps 118 along score 'lines 36.

Referring -also to FIGURES 2, 3 and 5, the lateral edges of iiap I16ar.edenedfrom'adjacent flaps 1'5 and"-17 along 'cut `lines V:orby .cuteoutportions as at 30, Land 311 respectively, which lines .or cut-.outsterminate -short of hinge lines 20 to 22 at laterally extending cutlines 40 lying substantially parallel to those hinge lines. Between cutlines 40 and the aforementioned hinge lines, the divisions between aps16 and adjacent flaps 15 and l17` are dened by cut score `lines 42impressed only partially through the blank material from the outside ofthe blank 'ice (the reverse side of the blank as depicted in FIGURE l).Cuts 40 are impressed completely through the blank material, anddivisions 310 and 31 and cut score lines 42 are precisely arranged forpu-rposes later to be detailed.

In the initial stage of the formation of a carton from the blank shownin FIGURE l, elements 13 and 14 are together folded `about hinge scoreline 3 to overlie Walls .11 and 12, land wall 10' is then folded abouthinge score line 1 to overlie the exterior surface of panel 14, to whichit is fastened by any suitable means, preferably an adhesive. Flaps 15are simultaneously adhered to the exterior surface of flaps 26, the.diagonally-cut lateral edges of ilaps 15 substantially coinciding withdiagonally hinge score lines 25. It is in :this form, commonly referredto as a glued shell or blank, that the carton is made by the cartonmanufacturer, for shipment to the packager who will set up, fill andseal the carton for shipment and sale of the contained product.

FIGURE 6 shows one end of the tube `formed by squaring of the shellpreviously described, the opposite end of the construction described ofcourse being identical thereto. Referring also to FIGURE 7 closing of anend of the carton is initiated by rst outfolding iiaps 16, 17 and 15,26. This outfolding results in a substantially planar cleavage of thecarton material intermediate of the surfaces, the cleavage beinginitiated at the conjuncture of cut lines 40, separations 30, 31 and cutscores 42, and progressing outwardly along cuts 40 and downwardly alongcut scores 42 as the outfolding continues. When the ycleavage lreachesthe ends of cut lines 40, the webs 50 of material which have thusseparated away from lflaps 15 to 1-7 tear downwardly to the hinge lines20 to 22. As seen in FIGURE 7, as the outfolding of aps 15 to 17 reachesthe point where they `lie in approximately the plane of the open end ofthe tubular shell, webs 50' by virtue of the tearing action describedhave been lformed to lie in substantially this same plane. This sameaction produces only a partial infolding of ilap 18 since that ilap isconnected to flaps 17 and 15--25 by fold panels or flaps 27 and 33.

Flap y18 is then folded over the open end of the tubular shell, as seenin FIGURE 8, fold flaps 27 `and 33 are adhered to underlying flaps 17and 15, 26, and sealing flap 19 is adhered to ap -16. At this same time,the overlying portions of ap 18 may be adhered to the exposed surfacesof webs 50.

Combined aps 15, 27 and 17, 33- are then folded in- Wardly, ,as seen inFIGURE 9, and yflap 16- with llap y19 adhered thereto is folded over theend of the carton and adhered in position as shown in FIGURE 10.

The carton, with one end thus closed, may then be filled with theproduct to be contained, and the other end then sealed in the samemanner as previously described.

The adhering and sea-ling of the various elements of the cartonconstruction, ras above described, may be achieved by any suitablesealing or adhesive means, such as glues of various sorts. However, itis preferred that this sealing be achieved through the use of athermoplastic or heat-sealing adhesive, which conveniently may beprovided by applying over the entire surface of the blank which willultimately form the interior of the carton .a heat-sealable coating,Such as, foi example, polyethylene. In an economical method ofmanufacture, the

.heat-scalable coating, such as polyethylene, may be continuouslyextruded onto a continuous 'web of paperboard, from which the blanks o-fFIGURE l are cut or stamped. It will be clear from the construction andmethod, as :above described, that there will result at each of thesealing points noted :a polyethylene-to-polyethylene contact, except atthe contact of the corners of aps 18 with the exposed surface of webs 50and at the seal of panel 14 to wall 10, permitting an exceptionally fine-leakproof seal.

In the construction described, all cuts, cut-scores and scoring may beimpressed into the carton :material from the same side or surface of theblank, specifically, that surface which will become the exterior of thecarton. However, referring also to FIGURE 4, a satisfactory constructionwill result if the transverse cut line 40, instead of being a cutcompletely through the material, is instead only a cut-score line 40aimpressed into the carton material from the interior surface of theblank. While the efficiency of the finished carton and of its erectionwill not thereby be adversely affected, this modification does requireimpression of the cut-score 40a into a surface of the blank opposite tothat from which the other cuts and scores commonly are impressed. Thisordinarily involves an additional and vseparate manufacturing step withattendant increased cost, and is therefore generally less desirable thanthe construction first described.

Referring also to FIGURE l1, the final tearing of the carton materialfrom the remote ends of cut lines 40, in the formation of webs 50, maybe facilitated `and given better directional control by providingdownwardly extending terminal cut portions 4Gb at the ends of cut lines40 or cut-scores 49a. The advantage resulting from this modification isreadily apparent from FIGURE 12, where the formation of webs 50 from themodified construction is shown The sealing of the extended overlappedflaps 16, 19, 17, 33 `and 15, 27 shown in FIGURE 8 may be accomplishedby running the extended flaps between conventional heatsealing barswhereby the thermoplastic heat-sealable coating will be actuated to forma leakproof seal. In conjunction therewith, a heating element may be`applied against the end of the carton closed as shown in FIG- URE 8 toactivate the coating on the interior surface of flap 18 to achieve aseal of the corner portions of that fiap to the webs 50. A similarapplication will seal flap 16 over the end of the carton to achieve thefinal closure shown in FIGURE l0.

It is preferred that the carton blank of FIGURE 1 be formed fromrelatively stiff paperboard, preferably of a thickness from about .OilOto .020 inch, in which range the material is of sufiicient strength toreact suitably to the application of heat-sealing temperatures andpressures, but not of such great stiffness as to make such applicationunduly difiicult. However, any suitable type and weight of lmaterial maybe employed, so long as it is capable of reasonably controlled planarsplitting to provide webs 50 and proper folding and adhesion of theelements in accordance with the foregoing description.

Also, as indicated, a polyethylene coating provides excellent resealing,both from the point of View of providing general leakproofness and ofproviding excellent sealing and handling characteristics, It ispreferred to coat the carton material with about l to 20 pounds ofcoating or extruded lm per ream (2880 sq. ft.) of carton material, but-any weight sufficient to achieve the objective will 'be satisfactory.It has also been found that particular wax blends may be used to providea satisfactory overall construction. As noted, it is not necessary inparticular uses that an overall coating or fil-m be applied to theblank, but rather it may be sufficient to employ a thermoplastic orother adhesive only in the areas in which a seal is-re quired.Obviously, in any of these constructions the resulting carton may bewrapped, overwaxed, or otherwise treated to provide primary oradditional leakproofness, improved printing or merchandising qualities,or other features. It will also be apparent that the carton couldinclude the web corner construction .at all four of its corners, ratherthan at only two as shown,

Although only certain modifications and preferred forms of thisinvention have been shown and described, it is clear that obviousdepartures from the disclosure herein may Ibe made without departingfrom the spirit of the invention. Accordingly, it is intended that theinvention is to be limited only as specifically set forth in theappended claims.

I claim:

1. A leakproof carton corner construction, the carton including a pairof main walls connected together along adjacent edges and an end closureflap hingedly connected to the end edge of each of said walls and foldedin overlapping relation to overlie the end of the carton substantiallynormally with respect to the walls, the leakproof construction beingprovided by an integral web of carton material lying in 'a planeparallel to and immediately inwardly of the adjacent aps -at the cornerof the carton and perpendicular to the Walls and comprising a layer ofcarton material separated from the inner surface of said flaps at saidcorner and integrally connected to said flaps of the carton immediatelyadjacent the hinge connection of the flaps to the walls.

2. In a paperboard blank adapted to form a carton, the blank beingdivided by cuts and scores to include opposed pairs of end and sidewalls and top and bottom closure flaps hinged to the ends of the walls,a leakproof corner construction comprising 4a first cut separating apair of adjacent closure flaps, said cut terminating outwardly of thehinge connection of said aps to the respective adjacent walls, and asecond cut through at least the inner surface of the blank extendinginto both of said flaps from the inner terminal end of said first cutand substantially perpendicular thereto, to provide a leakpreventing webover the corner of the carton formed from the blank upon outward foldingof said adjacent flaps.

3. A corner construction according to claim 2, in which said second cutis extended completely through the blank.

4. A corner construction according to claim 3, in which said cut yateach end terminates in a cut extending toward said 4hinge connection.

5. A corner construction according to claim 2, in which Said second cutat each end terminates in a cut extending towards said hinge connection.

6. In a paperboard blank adapted to form la carton, the blank beingdivided by cuts and scores to include opposed pairs of end and sidewalls and top and bottom closure flaps lhinged to the ends of thew-alls, `a leakproof corner construct-ion comprising ya first cutseparating a pair of adjacent closure flaps, said cut terminatingoutwardly of the hinge connection of said flaps to the respective-adjacent walls, a cut score impressed into the exterior surface of theblank and extending from said termination of the first cut to said hinge-connect-ion, and a second cut through at least the inner surface of theblank extending into both of said flaps from the inner terminal end ofsaid rst cut and substantially perpendicular thereto, to provide Ialeak-preventing web over the corner of the carton formed from the blankupon outward folding of said adjacent aps.

References Cited in the file of this patent UNITED STATES PATENTS2,485,235 Graf Octl 18, 1949 2,523,488 Williamson Sept. 26, 19502,652,186 Zinn Sept. l5, 1953 2,769,589 Moore Nov. 6, 1956

1. A LEAKPROOF CARTON CORNER CONSTRUCTION, THE CARTON INCLUDING A PAIROF MAIN WALLS CONNECTED TOGETHER ALONG ADJACENT EDGES AND AN END CLOSUREFLAP HINGEDLY CONNECTED TO THE END EDGE OF EACH OF SAID WALLS AND FOLDEDIN OVERLAPPING RELATION TO OVERLIE THE END OF THE CARTON SUBSTANTIALLYNORMALLY WITH RESPECT TO THE WALLS, THE LEAKPROOF CONSTRUCTION BEINGPROVIDED BY AN INTEGRAL WEB OF CARTON MATERIAL LYING IN A PLANE PARALLELTO AND IMMEDIATELY INWARDLY OF THE ADJACENT FLAPS AT THE CORNER OF THECARTON AND PERPENDICULAR TO THE WALLS AND COMPRISING A LAYER OF CARTONMATERIAL SEPARATED FROM THE INNER SURFACE OF SAID FLAPS AT SAID CORNERAND INTEGRALLY CONNECTED TO SAID FLAPS OF THE CARTON IMMEDIATELYADJACENT THE HINGE CONNECTION OF THE FLAPS TO THE WALLS.